1. Field of the Invention
The present invention relates to a rotary drier apparatus for drying rinsed semiconductor wafers.
2. Description of the Prior Art
A process of rinsing/drying semiconductor wafers has now conspicuously been improved in its throughput capacity owing to automation. It is the main method among many methods to effect the process described above to rinsing/drying carriers adapted to house 20 sheets of wafers therein in units carriers of two. A drier apparatus for use in such a process is of a type in which wafers are dried by rotation, wherein carriers serving to house the wafers are set interiorly of cradles mounted on a rotor, and any water adhering to the wafers is blown off by rotating the rotor. Such methods are for example described in Japanese Laid-Open Patent Publications No. 55-154736 and No. 56-8823.
A process of rotating and drying semiconductor wafers is adapted to keep the wafers horizontal and thereafter to allow a rotor to be rotated for easily removing waters. On the other hand, when the wafers are conveyed from one process to another, the wafers are supported vertically in their attitude in a carrier, and conveyed. Therefore, it is needed to alter the wafers from the vertical state to a horizontal one upon setting the carriers, including the wafers supported therein, on a rotary drier apparatus. A prior rotary drier apparatus for semiconductor wafers has a device to alter the attitude of a cradle to achieve the above object. The device comprises, for example a rod to push the cradle and an air cylinder to drive the rod.
However, such a prior rotary drier apparatus so equipped with the cradle attitude altering device suffers from some drawbacks that (a) hermetic sealing is insufficient at a connecting portion between a vessel and the attitude altering device, (b) cleanliness in the vessel is deteriorated since the attitude altering device goes in and out of the vessel in part, and (c) the construction of the rotary drier apparatus is complicated resulting in a large overall apparatus.